辽东大石桥组蛇纹石化大理岩中铀矿化特征及形成时代  

Geological features and dating of uraninite in serpentinized dolomite marbles of the Dashiqiao Formation in eastern Liaoning Province

作　　者：郭春影[1,2] 李子颖[1,2] 韩军[1,2] 徐浩[1,2] 白芸[1,2] 任忠宝 韩愉[4] 赵宇霆[4] GUO Chunying;LI Ziying;HAN Jun;XU Hao;BAI Yun;REN Zhongbao;HAN Yu;ZHAO Yuting(Beijing Research Institute of Uranium Geology, Beijing 100029, China;CNNC Key Laboratory of Uranium Resource Exploration and Evaluation Technology, Beijing 100029, China;CNNC Department of Geology and Mining, Beijing 100013, China;School of Earth Sciences and Mineral Resources, China University of Geosciences, Beijing 100083, China)

机构地区：[1]核工业北京地质研究院,北京100029 [2]中核集团铀资源勘查与评价技术重点实验室,北京100029 [3]中核集团地质矿产事业部,北京100013 [4]中国地质大学(北京)地球科学与资源学院,北京100083

出　　处：《地质通报》2017年第4期565-574,共10页Geological Bulletin of China

基　　金：国家自然科学基金项目<辽东古元古代碰撞造山过程的热液铀成矿作用:年代学约束>(批准号:41502097);国防科技工业局核能开发项目<华北陆块北缘铀多金属矿综合评价技术研究>;国土资源科技创新团队培育计划<铀矿成矿理论与深部找矿技术>

摘　　要：在辽东大石桥组蛇纹石化大理岩中新发现晶质铀矿矿化现象。晶质铀矿呈角砾状发育在蛇纹石化白云石大理岩中,并叠加有辉钼矿、黄铁矿等矿化。U-Pb同位素年龄测定显示,晶质铀矿形成于1763~1794Ma。EPMA U-Th-Pb化学年龄显示,晶质铀矿形成后经历了1512±20Ma的热事件改造,对应一次岩浆侵入事件。辽东地区经历了古元古代的裂谷拉张、碰撞造山、造山后伸展等重大地质事件。大石桥组中蛇纹石化大理岩中的铀矿化,以及连山关铀矿床、翁泉沟地区铁-硼-铀矿床的热液铀成矿作用均形成于古元古代晚期造山后/非造山区域伸展环境,可能与区域伸展体制下的地幔柱活动有关。In this study,the authors analyzed the geological features and ore-forming ages of the newly found uranium mineralization in serpentinized dolomite marbles to infer their regional metallogenic significance.The uranium mineralization in serpentinized dolomite marbles occurs as uraninite breccias imprinted by later sulfide mineralization such as molybdenite,pyrite.The U-Pb isotopic dating indicates that the uraninite was formed in1763~1794Ma.The in situ EPMA U-Th-Pb chemical dating of uraninite implies a thermal reworking event on uraninite at1512±20Ma,which is synchronous to a regional magmatic event.The eastern Liaoning Province underwent significant geological evolution in Paleo-Proterozoic,from early rifting to collisional orogenesis and post orogenic extension.The newly found uranium mineralization in serpentinized dolomite marbles and the uranium mineralization in the Lianshanguan U deposit and in the Fe-B-U deposits in the Wengquangou area were all formed in a post orogenic/unorogenic extensional environment possibly related to the mantle plume activity in regional extensional tectonic setting.

关 键 词：辽东 古元古代 大石桥组 铀成矿 地幔柱 

分 类 号：P619.14[天文地球—矿床学]